Physical fitness is recognized as essential to good health and longevity. Exercise, and particularly aerobic exercise, is an important element in achieving and maintaining physical fitness. For example, one of the leading causes of death in the United States is heart disease. Numerous studies have shown that consistent aerobic exercise will significantly reduce the risk factors associated with heart disease.
Aerobic exercise is available through many sports and activities, each with certain advantages and limitations. Cross-country skiing has long been regarded by fitness experts as one of the best overall aerobic activities because it is a total body endurance sport that aerobically conditions both the upper and lower body. Unfortunately, only a relatively small number of people have access to cross-country ski areas, and the sport is, of course, subject to season and weather. There are cross-country ski simulators, but those currently available require a high level of skill to use, are expensive, and provide resistance through a limited range of motion which reduces the effectiveness of the activity.
Other activities are more widely available. Currently, the most popular modes of aerobic exercise are walking, jogging, aerobic dance, stairstepping, and stationary cycling. Although these activities are beneficial if performed regularly, they do little to aerobically condition or tone the muscles of the upper body.
In an effort to increase the effectiveness of such activities, some individuals have used hand-held weights. However, several studies have shown that handweights are ineffective in enhancing weight loss or significantly improving cardiovascular parameters. Further, because of the ballistic nature of the forces involved, handweight users are more prone to shoulder injuries.
There have also been a variety of devices which include belts and elastic members with hand grips intended for use either alone or in conjunction with lower body activities, but none of these devices have proved entirely suitable in terms of effectiveness, safety and convenience. These devices do not allow the elastic members to be easily attached to and detached from both the belt and the handle or strap, thus making it difficult to change the resistance of the elastic members or to adapt the device for a variety of different exercises. Some devices have a flexible, non-elastic line which slides around the user's waist when the arms are alternately moved in a reciprocal motion, while others have non-sliding elastic cords fixed to a belt. These arrangements limit the range of motion, do not provide variable resistance based on whether one or both arms are extended, and do not allow flexibility of use in a wide variety of exercises.
Another problem with such known devices is that they have handles or hand grips which the user is required to firmly grip during use. Frequent use of such hand grips can cause overuse injuries in the wrist joint and the muscles responsible for gripping and hand movement. Conventional handles are difficult to use for individuals with hand or lower arm injuries such as carpal tunnel syndrome or "tennis elbow." They are also not recommended for cardiac rehabilitation patients or other persons with a heart condition, as statically tensing the muscles of the hands and forearms while performing aerobic exercise may result in coronary thrombosis. Conventional handles are also not adjustable to properly fit different sized hands.
Finally, the plain elastic members previously known are subject to wear and do not have sufficient elasticity to permit a full range of motion.